REACTIVE & FUNCTIONAL POLYMERS
·
2018
·
IF 2.975
Lei Lei,Hengchang Ma,Jiawei Lv,Tao Wang,Yuan Yang,Pei Yin,Ziqiang Lei,Yanfang Qin,Yucheng Ma,Wenhuan Yao
Materials hybrided by organic and inorganic partners via chemical bonds formation are able to display stable and multi-functional behaviors. Then, the versatile sensing platform could be established depending on their specific chemical and physical properties. In this research paper, we prepared the fluorescence materials (POSS-PDB and POSS-NTB) by a simple method. Among of them, POSS-NTB was verified as a mesoporous material with a narrowed pore diameter around 17 nm and the large Brunauer-Emmett-Teller (BET) surface area of 227 m 2 /g. Then, the solid powder of POSS-NTB was selected and evidenced as effective gas sensor toward CO 2 , N 2 and O 2 at 273 K under 1 atm pressure. Additionally, these fluorescence materials could be successfully applied as a pH sensor in the solution phase. Through combining biocompatible POSS and fluorescent molecules, POSS-NTB could enter into the cells and aggregate in the cytoplasm successfully.
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PROPELLANTS EXPLOSIVES PYROTECHNICS
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2018
·Vol. 43
·期 7
·637-641
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IF 1.749
Naimeng Song,Jianchao Liu,Guoying Zhang,Zhenzhan Yan,Hongxu Gao,Li Yang
This paper describes the preparation of two combustion catalysts Tannin-Fe (Ta−Fe) and Phloroglucinol-Fe (Ph−Fe) by spray drying. The particle size and morphology of the particles are observed by scanning electron microscopy (SEM). The results of SEM image show that the particles are regular spherical and very good dispersion. The diameter of most spherical particles is about 1 μm. The effects of Ta−Fe and Ph−Fe on the thermal decomposition of RDX and AP were tested by differential scanning calorimeter (DSC). DSC dates show that Ta−Fe and Ph−Fe can advance the high temperature exothermic peak of AP 18.0 °C and 16.1 °C, respectively. The burning rates illustrates that both Ta−Fe and Ph−Fe can significantly increase the combustion rate of HTPB propellants. The formulation with 2 mass% Ta−Fe shows an average 21.31 % increase in burning rate and has a low value of the exponent n=0.48. The formulation with 2 mass%Ph−Fe has a burning rate 20 to 60 % larger than that of the initial AP/HTPB/Al formulation, and has a lowest exponent n=0.45.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Suyun Zhang,Xinxin Xiao,Taotao Lv,Xiaomeng Lv,Botao Liu,Wei Wei,Jun Liu
Exploring efficient and economical Pt-free electrocatalysts is of great significance for the electrocatalytic hydrogen evolution reaction (HER). However, the rational design on an industrial scale is a formidable challenge. Herein, we reported a facile calcination at controlled temperatures to fabricate rationally assembled cobalt nanoparticles embedded in defect-rich N-doped carbon nanotubes (Co-NCNTs), which was derived from low-cost dicyanadiamide thermally polymerized with cobalt precursor forming metal-organic frameworks, then further calculation leading to final products. The as-obtained samples were endowed with high content of N as electrocatalytic active site, defect-rich structure and excellent synergistic effect between cobalt nanoparticles and carbon nanotubes toward electrocatalytic HER . As expected, Co-NCNTs were highly active and long-term stable with onset potentials of c.a. 15 mV in acidic electrolytes (0.5 M H 2 SO 4 ), 70 mV in alkaline (1 M KOH) and 300 mV in neutral media (pH 7). Specially, to achieve the current density of 10 mA cm −2 , the overpotential of 103 mV in acid, 204 mV in alkaline and 337 mV in neutral media was obtained. The enhanced HER performance was discussed in detail by adjusting the molar ratio of precursor and metal species. Moreover, the present synthetic route is easy to scale up and expand to other non-noble metal and alloy.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2018
·
IF 3.909
Ying Wang,Feng Bai,Qiang Luo,Mingliang Wu,Gang Song,Hongmei Zhang,Jian Cao,Yanqing Wang
Lycium barbarum polysaccharide-doxorubicin (LBP-DOX) nanoparticles were synthesized via a one-step Schiff base reaction between oxidized Lycium barbarum polysaccharide (oxidized LBP) and doxorubicin (DOX). The structure of LBP-DOX nanoparticles was characterized by multi-spectral methods, 1 H nuclear magnetic resonance ( 1 H NMR), transmission electron microscopy (TEM), and thermo gravimetric analysis (TGA). The rheological properties of LBP-DOX nanoparticles were studied. With the increase of shear rate, the viscosity of LBP and LBP-DOX nanoparticles gradually decreases at 25 °C. Under the same strain, the storage modulus (G′) and loss modulus (G″) of LBP-DOX nanoparticles were inferior to LBP. The DOX release from LBP-DOX nanoparticles was pH-dependent and was accelerated by decreasing pH. Cytotoxicity study showed that the LBP-DOX nanoparticles have significantly enhanced cytotoxicity in vitro, especially for human Hepatic cancer cell line HepG2.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Xiao Shi,Yumin Ye,Hui Wang,Fu Liu,Zhijie Wang
We present the design of a novel pH-responsive drug release system that is achieved by solventless encapsulation of drugs within a microporous membrane using a thin capping layer of biodegradable poly(methacrylic anhydride) (PMAH) coating. The coating was synthesized via a mild vapor polymerization process, namely, initiated chemical vapor deposition, which allowed perfect retention of the anhydride groups during deposition. The synthesized polyanhydride underwent degradation upon exposure to aqueous buffers, resulting in soluble poly(methacrylic acid). The degradation behavior of PMAH is highly pH-dependent, and the degradation rate under pH 10 is 15 times faster than that under pH 1. The release profile of a model drug rifampicin clearly exhibited two stages: the initial stage when the coatings were being degraded but the drugs were well stored and the second stage when drugs were gradually exposed to the medium and released. The drug release also showed strong pH responsiveness where the duration of the initial stage under pH 1 was more than 7 and 3 times longer than that under pH 10 and 7.4, respectively, and the release rates at pH 7.4 and 10 were significantly faster than that at pH 1. The pH-dependent degradation of the encapsulant thus enabled good preservation of drugs under low-pH environment but high drug release efficiency under neutral and alkaline environment, suggesting potential applications in site-specific drug delivery systems.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2018
·
IF 2.829
Xiaoran Li,Vasil M. Garamus,Na Li,Yabin Gong,Zhe Zhe,Zhenfen Tian,Aihua Zou
This study was aimed at preparing a highly dispersed and pH-sensitive mesoporous silica nanoparticles (MSNs) carrier via surface modification with polydopamine (PDA) and polyethylene glycol (PEG) i.e. [email protected] Small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) measurements suggested that hexagonally structured MSNs (type MCM-41) with the layer of PDA and PEG of thickness ∼20 nm were successfully prepared. Bovine serum protein (BSA) adsorption experiments showed that less protein was absorbed by [email protected] after the anchoring of PEG, which confirmed the stealth properties of prepared carriers. Doxorubicin hydrochloride (DOX) was used as the model drug to be encapsulated into [email protected] (DOX/ [email protected] ). The DOX/ [email protected] had relatively high entrapment efficiency and drug loading up to 94.2% and 31.4%, respectively. The in vitro release profile of DOX/ [email protected] exhibited pH-responsive and gradual drug release. Cytotoxicity assay showed that DOX/ [email protected] had comparable cytotoxicity to A549 cells compared to pure DOX. The intracellular distribution of DOX/ [email protected] was imaged using confocal laser scanning microscope. It points that PDA and PEG can play “gatekeeper” and stealth roles for MSNs as promising nanocarrier for cancer treatment.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Yuan Chen,Tongming Chen,Xiaoju Wu,Guowei Yang
As delafossite type of metal oxide materials, CuMnO 2 nanoflakes show great promise for optoelectronics applications due to their excellent optical, electric and multiferroic properties. Here, we for the first time demonstrate that CuMnO 2 nanoflakes possess intrinsic activity of mimicking enzymes of peroxidase, oxidase and catalase . Through modulating the pH value, CuMnO 2 nanoflakes can catalyze the reduction of oxygen (O 2 ) and hydrogen peroxide (H 2 O 2 ) at acidic environment, and the decomposition of H 2 O 2 to produce O 2 at alkaline pH. The mechanism of their peroxidase-like activity has been proposed as the generation of hydroxyl radical ( OH). Based on the colorimetric reaction of CuMnO 2 nanoflakes and the hindrance of the peroxidase-like activity in the presence of H 2 O 2 and l -cysteine, a simple platform for l -cysteine detection with low detection limit of 11.26 μM has been developed. Compared with other bimetallic oxides, CuMnO 2 nanoflakes exhibit higher sensitivity and lower detection limit towards l -cysteine. Surprisingly, the proposed method for l -cysteine estimation can also be used in milk samples. These findings pave the way for further investigation about the catalytic activity of CuMnO 2 nanoflakes and make them a promising candidate for biomedical applications.
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RSC Advances
·
2018
·Vol. 8
·期 56
·32193-32199
·
IF 2.936
Yiyuan Tang,Kai Chen,Jiacheng Li,Yuhong Feng,Gaobo Yu,Longzheng Wang,Xinyu Zhao,Yang Peng,Quan Zhang
In this study, a pH-responsive amphiphilic alginate (Ugi-Alg) was synthesized via Ugi reaction without using a catalyst. The structure of Ugi-Alg was confirmed by FT-IR and 1H NMR spectroscopy. Amphiphilic alginate can form micelles in an aqueous medium due to it's amphiphilic nature.. The impacts of Na+ concentration and pH on the micelle size were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The dynamic light scattering observations showed that micelle size increases with the decrease in Na+ concentration in aqueous solution. However, the micelle size decreases first and then increases as the pH value decreases from 5.3 to 2.0. Transmission electron microscopy confirmed that the mean size of micelles is 30–200 nm. In addition, a model hydrophobic pesticide (acetamiprid) was loaded in the micelles. The encapsulation efficiency and release behavior of micelles were studied, which could be controlled by Na+ concentration and pH. The results indicated that encapsulation efficiency of acetamiprid increases from 55% to 96% due to the increase in Na+ concentration from 0.01 M to 0.3 M. Moreover, with the decrease in pH from 5.3 to 2.0, encapsulation efficiency increases from 55% to 80%. Furthermore, the data of acetamiprid release kinetics could be well-fitted by the Weibull model.
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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2018
·Vol. 18
·期 7
·4464-4470
·
IF 1.354
Ji Fan,Zhang Kun,Li Jie,Gu Yuanliang,Zhao Jinshun,Zhang Jianfeng
Cancer chemotherapy has limitations such as nonselective distribution of drugs, detrimental side effects on normal tissues; here we reported a smart pH and magnetic sensitive drug delivery system (DDS) based on PEGylated Fe3O4 superparamagnetic nanoparticles. The
citric-coated Fe3O4 (CIO) nanoparticles were firstly synthesized and further functionalized by biocompatible poly(ethylene glycol) bis(carboxymethyl ether) (COOH-PEG-COOH), thus PEGylated CIO (GCIO) nanoparticles were obtained. Doxorubicin (DOX) was conjugated as a model
drug to the nanoparticles via hydrazone bond. The roughly sphere GCIO nanoparticles were comparatively strong magnetism with high drug loading capability (~89%) in relatively uniform size. Drug release study revealed that the GCIO-DOX performed pH-responsive drug-release properties. MTT assay
demonstrated that GCIO nanoparticles possessed low cytotoxicity and good physiological stability. Further, cell viability results indicated that the GCIO-DOX showed effective cytotoxicity only a bit lower than free DOX. All obtained data indicated that the combined pH-responsive and magnetic
multifunction drug delivery system can has excellent potential applications in cancer therapy.
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MATERIALS AND MANUFACTURING PROCESSES
·
2019
·
IF 3.35
Chunyu Wang,Yuhuan Bu,Shenglai Guo,Zhuang Cai,Baojiang Sun,Guangquan Li,Zhonghou Shen
pH-sensitive water and oil dual-absorption material (WODAM) has been successfully synthesized through microemulsion polymerization. Firstly, microemulsions prepared with monomers were analyzed by pseudo-ternary phase diagram. In addition, conductivities of microemulsions were tested to identify microemulsion types. Meanwhile, the factors that affected microemulsion types were analyzed. Then WODAMs were prepared, and the chemical structure was characterized using Fourier transform infrared (FTIR) spectroscopy. Liquid absorption tests indicated that both monomer ratio and microstructure of WODAMs had influences on their water absorption rate (WAR) and oil absorption rate (OAR). In addition, pH sensitivity tests showed that WODAM absorbed much water in neutral and weak alkaline solutions, but little water in strong alkaline solutions. What’s more, liquid absorption tests in cement slurry filtrate (CSF) showed that WODAM was applied to oil well cement. This paper prepared a new self-healing agent, and is of great significance to realize self-healing cement in complex downhole condition.
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SENSORS
·
2019
·Vol. 19
·期 17
·3801
·
IF 3.031
Tingyu Wang,Guoqing Chen,Lei Li,Yamin Wu
In this report, high-brightness green carbon dots were successfully prepared using 3,5-diaminobenzoic acid as the sole precursor and synthesized in one step using a solvothermal strategy. Under the excitation of 365 nm ultraviolet light, the quantum yield of carbon dots is as high as 53.8%. Experiments revealed that the carbon dots are highly carbonized and the surface is rich in amino and carboxyl groups. The synthesized carbon dots have good water solubility, and are resistant to ions and temperature. The fluorescence intensity of CDs is sensitive to pH changes and is linearly correlated with the pH in the near-neutral range (pH = 6.0 to 9.0). Our experiments showed that carbon dots were sensitive and accurate fluorescent probes for measuring the pH value of drinking water, which could provide an effective method for measuring the pH value of water in the future.Keywords:carbon dots;solvothermal;3,5-diaminobenzoic acid;pH;fluorescent probe
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MOLECULES
·
2019
·Vol. 24
·期 16
·2923
·
IF 3.06
Piaopiao Chen,Iqra Ilyas,Su He,Yichen Xing,Zhigang Jin,Chaobiao Huang
Polymer dots (Pdots) represent newly developed semiconductor polymer nanoparticles and exhibit excellent characteristics as fluorescent probes. To improve the sensitivity and biocompatibility of Pdots ratiometric pH biosensors, we synthesized 3 types of water-soluble Pdots: Pdots-PF, Pdots-PP, and Pdots-PPF by different combinations of fluorescent dyes poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO), poly[(9,9-dioctyl-fluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadazole)] (PFBT), and fluorescein isothiocyanate (FITC). We found that Pdots-PPF exhibits optimal performance on pH sensing. PFO and FITC in Pdots-PPF produce pH-insensitive (λ = 439 nm) and pH-sensitive (λ = 517 nm) fluorescence respectively upon a single excitation at 380 nm wavelength, which enables Pdots-PPF ratiometric pH sensing ability. Förster resonance energy transfer (FRET) together with the use of PFBT amplify the FITC signal, which enables Pdots-PPF robust sensitivity to pH. The emission intensity ratio (I517/I439) of Pdots-PPF changes linearly as a function of pH within the range of pH 3.0 to 8.0. Pdots-PPF also possesses desirable reversibility and stability in pH measurement. More importantly, Pdots-PPF was successfully used for cell imaging in Hela cells, exhibiting effective cellular uptake and low cytotoxicity. Our study suggests the promising potential of Pdots-PPF as an in vivo biomarker.Keywords:Pdots;semiconductor polymer;FRET;pH sensing;cell imaging
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